Single-zone pulverizing apparatus



Aug. 20, 1929. BEACH 1,724,895

SINGLE ZONE PULVERIZING APPARATUS Filed May 5, 1926 INVENTOR DAVID f1:BEACH CI/"I Q, 9L 0'14- a) ATTNEY WITNESSES Patented Aug. 20, 19 29.

UNITED STATES.

1,724,895- PATENT OFFICE.

DAVID R. BEACH, 015 WORCESTER, MASSACHUSETTS, ASSIGNOR TO RILEY STOIERCORPORATION, OF WORCESTER, MASSACHUSETTS, A CORPORATION OF MASSA-CHUSETTS.

SINGLE-ZON E PULVERIZING APPARATUS.

Application filed May 5,

This invention relates to pulverizing apparatus and more particularly toa device of the beater type shown in the reissue patent to Blyth N 0.16,229, which pulverizes such material as coal by means of revolvingimpact members.

Apparatus of this type, as previously made, involves the use of twoseparate pulverizing zones on opposite sides of a rotatable disk,-

10 with the fuel inlet and outlet openings adjacent to the axis of thedisk. The material is pulverized by means of interfitting sets of pegsmounted on the rotary disk and the stationary casing Walls respectively.If the fuel to be pulverized is likely to include tramp iron it has beennecessary to employ some form of separator in connection with the fuelfeeding apparatus so as to prevent such hard foreign bodies fromentering the casing and breaking the pulverizing pegs, thus making itnecessary to shut down the machine for repairs. Moreover, the use ofpegs to crush the coarse material preliminarily is sometimesinadvisable, owing to the fragile nature of the impact members.

It is accordingly one object of this invention to overcome suchdifficulties and to provide a beater type of pulverizer which willhandle the ordinary run of coal, or other material, and eliminate safelythe hard foreign bodies without interfering with the pulverizingoperation.

It is a further object to provide a single zone pulverizing apparatus ofsimple construction which will crush coarse material and grind it to adesired and regulatable degree of fineness, and which will operateefficiently to produce a substantially uniform product.

\Vith these and other objects in view as will be apparent to one skilledin the art, this invention resides in the combination of parts set forthin the s ecification and covered by the claims appenci ed hereto.

Referringto the drawings in which like reference numerals indicate likeparts:

Fig. 1 is a vertical section on the line 1-1 of Fig. 2 of a machineembodying one form of my invention;

Fig.2 is a section on the line 22 of Fig. 1

Fig. 3 is a detail showing the preferred method of mounting the pegs;

Fig. 4 is an isometric View showing one of the swing hammers;

1926. Serial a... 106,982.

Fig. 5 is a perspective rejector blades; and

Fig. 6 is a detail showing the preferred method of mounting the swinghammers.

In accordance with the invention, it is proposed to pulverize the coarsematerial completely to a fine size in a single pulverizing zone. This isaccomplished by means of revoluble heaters, arranged to pulverize thematerial as it passes inwardly towards a centrally located outlet. Inorder to insure com- 35 plete pulverization of the material, the coarsematerial is fed into the apparatus through an inlet adjacent to theperipheral path of the heaters, and the finely ground material iswithdrawn b means of an air current through an outlet a jacent to thecenter of the apparatus, so that the material is obliged to pass towardsthe center of the machine against'the centriftigal force set up by therevolving impact members. As a result, coarse particles will be thrownback into the pulverizing zone and broken further, until of such sizethat they will float like dust particles in a cloud through the exitorifice. The heaters may be mounted on various "forms of rotor and thecasing correspondingly shaped, and in the preferred form the rotor isdisk shaped and the heaters may consist of pegs arranged on one sidethereof. The number, size and location of the pegs affects the finenesscharac.. teristics of the ground material: For grinding fuel, I preferto employ a setjof stationary pegsarranged to cooperate with therevoluble heaters and these may be mounted on the casing wall close tothe ath of the beaters. An inlet for the material is provided at oneside and adjacent to the periphery of the rotating member, and at thebottom of the machine adjacent to the inlet a tramp iron receptacle maybe arranged to catch the hard foreign bodies therein. For certain typesof material, a preliminary crushingoperation is desirable, and we mautilize heavy impact members to strike the rst blow. We find itdesirable in such cases to utilize yielding or swinging hammers whichcooperate with the peripheral wall of the casing to break the materialinitially and yet yield sufficiently, when large, hard bodies are met,to prevent breaking the apparatus. The tramp iron receptacle and theswing hammers are not found necessary for pulverizing certain materialsand one or both of these may be omitview of one of the 5 and assembly ofthe parts within the cas-' ing, the casing may be split 'on a horizontalplane, as shown in Fig. 1, the lower part being mounted on a suitablebase 14 and the upper p art removably fastened thereto by means 'ofbolts passing through the flanges 15.

Passing centrally through the two chambers and the connecting passage 13is a shaft 16 suitably mounted in bearings illustrated diagrammaticallyas bosses 17 and 18 on the outer sides of the casing. The shaft 16 isadapted to be rotated preferably at high speed by means of suitabledriving mechanism indicated by the half coupling 19 located on one endof the shaft 16, which may be connected with a similar part on a drivingshaft.

Keyed to the shaft 16 within the chamber is a disk 20 located close tothe outer wall 21 "of the casing and spaced by .a considerable distancefrom the other wall 22 thereof. The impact members for finel crushingthe aterial preferably take the orm of pegs, one set of which issuitably fastened on the-rotary disk 20 and another set on thestationary casing wall 22; The preferred peg arrangement comprisesseveral rows of pegs 24 mounted in concentric circles on the lnner faceof the disk 20 which intermesh with rows of stationary pegs 25projecting inwardly from the walls 22 of the casing.

The pegs may be mounted in any suitable mannenbut as shown particularlyin Fig.3

they preferably consist of iron pegs (3356111 ferrules 27 of drawnmetal. These ferrules have "flanges 28 integral therewith by which thepegs may be supported in place. For this purpose, the disk 20 isprovided with a recess adapted to carry therein a clamping plate 29which may be made in several parts i and suitably bolted to the disk 20.The disk 20 is provided with holes 30 which are slightly larger than theferrules 2'Zyand the pegs are so mounted in these holes that the flanges28 are'held securely clamped between'the plates 29 and 20 with theferrules .centrally located in the holes. This construction is such thatthe slight resiliency ofi'the ferrule flanges may be brought into-playto prevent excessive shocks from breaking the pegs 24, The

pegs 25 may be similarly mounted between the casing wall 22' and atwo-part annular plate 32 which is revolubly mounted about the ring 33located adjacent to and concentrio with the outlet opening in the plpe13. These parts are so arranged that the plate 32 may be rotated aboutthe ring 33 when the upper half of the casing 10 has been removed,thereby-permitting ready access to any one of the pegs mounted on thecasing. These pegs, as will be understood, are carried in holes in theplate 32 and the plate is clamped to the casing wall 22 by means of capscrews inserted from the outside.

The inlet to the apparatus comprises, as shown particularly in Fig. 1,an enlargement at one side of the pulverizer casing 10 terminating in afeed pipe 40 which is adapted to beconnected ordinarily to a suitableauto matic feeding apparatus arranged to feed material at a desired rateto the machine. At the lower end of the space 41 between the disk 20 andthe outer wall forming this inlet area is a space devoted to thereception of tramp iron or other hard foreign bodies. For.

this purpose the lower portion42 ofthe end wall of the casing isarranged to flare outwardly'away from the rotor 20 in a manner to forman opening 43 within which the tramp iron may be deposited, and thisopening may beclosed by means of a slide 44 or other suitable device topermit the removal of the tramp iron from the machine.

As will be observed, the material enters the pulverizer casingsubstantially tangen tially to the edge of the disk 20 and if the diskis rotating downwardly at that side then thematerial is drawn into thepulverizing zone in the direction indicated by the arrow in Fig. 1 andit is then moved in a spiral-like path gradually toward theoutlet'opening in the pipe 13. If a piece of heavy tramp iron shouldfall into the casing, it might strike the pegs and so break them, and inorder to insure the heavier matter being sufficiently crushed beforethey can strike the pegs and to aid in depositing such foreign-bodies inthe tramp iron receptacle 43, I preferably make use of revolving swinghammers mounted on the disk adjacent to its periphery in the path of theentering material. These swing hammers are of such size and so arrangedthat as they revolve they will give the entering material a sharp blowand crush it preliminarily. These hammers 45 are preferably mounted onthe inner side of the disk 20 and are'of such a size as to sweepsubstantially the entire area of the casing so that all. materialentering the casing must be struck by them.

To this end, ;I prefer to form each swing a hammer in a T shape and tosuspend the hammer from the lower endof the T so that it may swingfreely as it is revolved. A simple form of mounting may comprise, asillustrated particularly in Fig. 6, a heavy peg 47 having a flange 48mounted between the plate 29 and the disk 20. The hammer 45 is providedwith a hole 50 so for the swing hammer arranged that the peg may beswingingly mounted on the reduced end 51 of the peg 47, and in order tohold the hammer in place, a collar 52 is mounted on a still furtherreduced end ofthe peg 47 and this is held in place by a nut 53 threadedon'the extreme end of the peg. The outer head 55 of the T-shaped swinghammer is very massive and arranged to strike the material a hard blow.In order to receive the wear on the interior of the casing caused bythese hammers crushing material between their fa'ces and the casing aset of wear' plates 56 may be provided and these may be corrugated asshown in order to provide extra crushing surface against which thehammers ma act.

In a machine of the type, the pegs 24 and 25 may extend nearly the fulldistance bee tween the rotating disk 20and the opposite casing wall soas to make sure that all of the material is subjected to the impactblows of the pulverizing peg members, and in such a construction one mayutilize a greater number of rows of pegs than shown in the drawing, inwhich case the rows adjacent to the axis of the disk serve as rejectorswhich throw back into the path of the more rapidly revolving pegs suchmaterial as has not. been finely pulverized. The preferred form of rejector, however, is shown in the drawing and comprises revolving arms 60mounted so as to sweep across the exit 61 which communicates with thepipe 13. These rejector blades may comprise U-shaped members so mountedthat the'open side faces in the direction of revolution. Each blade maybe fashioned as a casting having a base member 62 shaped to fit within agroove in the sleeve 63 keyed to the shaft 16. The wall 64 is slightlylonger 1 than the wall 65 so that the blade may travel within and closeto the beveled face 66 of the 7 ring 33. This rejector, it willtherefore be seen, is so shaped and positioned that it will sweep acrossthe entire exit orifice and'due to its rapid revolution and because ofits width it will prevent the escape of coarse particles from thecasing.

The material may be drawn through the casing by means of a fan 70 ofany'suitable construction mounted on the shaft 16 within the chamber 12.The material is drawn from the pulverizer chamber 10 through the conduit13 into the fan fasing and is then forced outwardly through the opehing72 which communicates with a pipe adapted to convey the material eitherto the burner of a furnace or to any other desired location. It is, ofcourse, essential that the fan have a capacity more than sufiicient toovercome the fan action of the pegs and swing hammers in the vpulverizer casing and that it'deliver the ma terial at the desiredvelocity. In order to insure the regulatable introduction of air intothe pulverizer casing, any suitable pro- 7 vision may be made, but Ihave shown this 24 short, a space is provided between their outer endsand the plate 32, so that such fine material may travel directly to theexit orifice and if sufficiently fine pass between the rejector bladesas a cloud of dust borne on the current of air drawn therethrough. 'If,however, the material is too coarse to pass the rejector blades, then itis struck by them and hurled against the beveled face 66 of the ring 33and thrown back into the path of the revolving pegs 24, where it issubjected to a further pulverizing action.

If the stationary pegs 25 are omitted entirely, there is nothing tohinder the whirling movement of the material in the machine except thefriction against the interior of the casing. Under these conditions, thematerial will revolve with the rotor at a speed closely approaching thatof the rotor, and this results in a very pronounced centrifugal force.Hence. only the finest of material can be drawn inwardly towardthecenter and pass out of the machine. While this extremely finegrinding is desirable for certain puroses, in many instances it isunnecessary. y utilizing stationary pegs, it is possible to reduce thewhirling movement of the material, and thus permit coarser'particles tobe withdrawn against centrifugal force. This arrangement also results ina marked reduction in the power required for driving the machine. Byvarying the number and arrangement of the pegs, the degree of finenessof the product can be controlled as desired.

The operation of the machine will be apparent from the above disclosure.If the disk is rotated in the direction shown by the arrow in Fig. 1then the action is substantial ly as follows: Material is fed into thepipe- 40 and asuppl of air is admitted through openings 74. he rapidlyrevolving swing hammers 45 strike the material as it enters the machineand drag it between the ham-. mers and the liner plate 56 of the casing.The tramp iron finds its way to the receptacle 43. The suction of theair caused by the rotation of thefan 70 causes the mate- V is subjectedto the centrifugal screening acto such a degree of fineness that it willthen travel as a cloud of dust on the air through .theexit and throughthe'fan casing.

' I It will therefore be seen that I have provided a very simple form ofpulverizer in which the material is pulverized inasingle zone and by asingle course of treatment. This type of machine will pulverize thematerial finely, since coarse material cannot escape through the exituntil it, is so fine that it will travelas a cloud of dust. If a foreignbody enters the casing and does not go immediately into the tramp ironreceptacleit will not ordinarily break the swing hammers butthey'willyield slightly and cause the tramp iron to be carried around the casingand ultimately to be deposited again in the, If such tramp receptaclerovided therefor. iron shoul escape into contact with the pegs, they arenot so'likely to be broken because they will merely hurl the iron backinto the path of the revolving hammers and centrifugal force willultimately tend to deposit it in the receptacle 43.

Having thus described my invention, what I claim as new, and desire tosecure by'Letters Patent, is:

1. A pulverizing apparatus comprising a hollow casing of substantiallycylindrical shape which has a centrally located outlet in one of its endwalls, apipe forming a localized inlet for the material to be pulverizedwhich opens into the casing at the periphery there- 0 means to move astream of air from the periphery of the casing to the outlet, a rotormounted within the casing with its axis con-' centric with the outlet,said rotor being spaced from that end wall of the casing in which theoutlet is located so as to form a single pulverizing zone, meansincludin a' set of beater elements on said rotor revollible between theinlet and'the outlet which serve to break the material by successiveimpacts thereagainst and screen the coarse from the fine particles,whereby only a cloud of pulverized material borne on the air current mayescape from the casing.

2. A pulverizing apparatus comprising a casinghaving a centrally locatedoutlet in one wall, a set of beater pegs revoluble about an axis passingadjacent to the outlet, a set of stationary pegs on the casingcooperating with the revoluble pegs to pulverize material fed thereto,means forming an inlet for feeding coarsematerial directly into thecasing ad acent to and outside-of the peripheral path of the beaters,said beaters being spaced from the outlet and so constructed as to setup a centrifugal force tending to move the coarse particles towards theeriphery" of the casing,

and a fan associate thefiewith to draw a cloud of the finely pulverizedmaterial. and

force.

3. A pulverizing apparatus comprising a substantially cylindrical casinghaving a v centrally located outlet, a rotor, axially concentric withsaid outlet and located close to one end wall of the casing to form asingle pulverizing zone, revoluble and stationary impact bodies on saidrotor and the opposite casing wall respectively which are arrangedconcentric with said outlet, means forming a single inlet to delivercoarse material adjacent the periphery of the rotor, and a fan fortransporting the finely divided material on a current of air from theinlet to the outlet,

said parts being so constructed and arranged that the material issubjected to the centrifugal screening action of the impact bodies as itpassestowards the outlet on the air current.

4. A pulverizing apparatuscomprising a substantially cylindrical casinghaving a centrally disposed outlet, a shaft concentric with said outlet,a rotor mounted on said shaft,

impact bodies mounted on said rotor to re-- \ly to the impact members,means forming a receptacle to receive hard foreign bodies entering theinlet, and means to pass a current of air through the machine from theinlet to the outlet and transport a dust cloud thereon.

5. A single zone pulverizing apparatus comprising a casing having acentrally disv posed outlet, a rotor having its axis adjacent to theoutlet, impact members on the rotor revoluble about the outlet, an inletpipe for feeding coarse material to the peripheral portion of the casingand directly to the impact members, yielding impact bodies on the r0;

tor to give a preliminary crushing blow to the material and means fortransporting a ,currentofv air through the casing. I

6. Afpulverizing apparatus comprising a casing having a centrallylocated outlet, a rotor axially concentric with the outlet and arrangedat one side to form a. single pulverizing zone, swing hammers on therotor adjaeent to the periphery of the casing which are arranged to give-a preliminary crushing blowto the material, revoluble and stationarypegs on the rotor and the opposite casing wa 1 respectively which arelocated between v the hammers and the outlet, means forming an inlet-for delivering coarse material di-- rectly" to said hammers, and meansfor trans- Rportin a current of air and a cloud of pulverize materialthrough the casing to the outlet against'the centrifugal action of the.

hammers and pe s.

7. A pu'lvlerizmg apparatus comprising a casing having a centrallylocated outlet, a rotor having its axis adjacent to theoutlet,

means forming an inlet to feed coarse material into the casing at theperiphery of the rotor, impact bodies on the rotor between the inlet andthe outlet to pulverize the material, a revoluble rejector adjacent tothe outlet to prevent the exit of coarse particles, and means totransport a current of air through the casing.

8. A pulverizingapparatus comprising a casing having a centrally locatedoutlet, a

rotor arranged axially concentric with the outlet to form a singlepulverizing zone, heaters on the rotor, means forming an inlet to feedmaterial into the casing directly to the periphery of the rotor, andmeans forming a receptacle for hard foreign bodies located in the pathof the incoming material.

9. A pulverizing apparatus comprising a casing having a singlepulverizing chamber,

means providing a centrally located outlet from said chamber, a rotormounted with its axis adjacent to said outlet, means to feed materialand air directly into the casin adjacent to the periphery of saidchamber, eaters on the rotor revoluble about the outlet and adjacent tothe peripheral inlet which are arrangedto pulverize the material bysuccessive impacts and to screen the coarse particles from the fine onesas it passes inwardly towards the outlet against centrif ugal force, andmeans to pass a current of air through the casin at a rate required, totransport a cloud 0% pulverized material therefrom.

' Signed at Worcester, Massachusetts, this 30th day of April, 1926.

DAVID K. BEACH.

